locks-event-category.md

title	Locks Event Category | Microsoft Docs
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ms.date	03/14/2017
ms.prod	sql
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ms.technology	supportability
ms.topic	conceptual
helpviewer_keywords	Locks event category [SQL Server] SQL Server event classes, Locks event category event classes [SQL Server], Locks event category lock escalation [SQL Server], locks event category
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author	stevestein
ms.author	sstein
monikerRange	=azuresqldb-current||>=sql-server-2016||=sqlallproducts-allversions||>=sql-server-linux-2017||=azuresqldb-mi-current

Locks Event Category

[!INCLUDEappliesto-ss-xxxx-xxxx-xxx-md] Use the event classes in the Locks event category to monitor locking activity in an instance of the [!INCLUDEmsCoName] [!INCLUDEssDEnoversion]. These event classes can help you investigate locking problems caused by multiple users reading and modifying data concurrently.

Because the [!INCLUDEssDE] often processes many locks, capturing the Locks event classes during a trace can incur significant overhead and result in large trace files or tables.

In This Section

Topic	Description
Deadlock Graph Event Class	Provides an XML description of a deadlock.
Lock:Acquired Event Class	Indicates that a lock has been acquired on a resource, such as a row in a table.
Lock:Cancel Event Class	Tracks requests for locks that were canceled before the lock was acquired (for example, to prevent a deadlock).
Lock:Deadlock Chain Event Class	Monitors when deadlock conditions occur and which objects are involved.
Lock:Deadlock Event Class	Tracks when a transaction has requested a lock on a resource already locked by another transaction, resulting in a deadlock.
Lock:Escalation Event Class	Indicates that a finer-grained lock has been converted to a coarser-grained lock.
Lock:Released Event Class	Tracks when a lock is released.
Lock:Timeout (timeout > 0) Event Class	Tracks when lock requests cannot be completed because another transaction has a blocking lock on the requested resource. This event occurs only in situations where the lock time-out value is greater than zero.
Lock:Timeout Event Class	Tracks when lock requests cannot be completed because another transaction has a blocking lock on the requested resource.